AN ABSTRACT OF THE DISSERTATION OF Matthew W. Loewen for the degree of Doctor of Philosophy in Geology presented on December 16, 2013. Title: Volatile Mobility of Trace Metals in Volcanic Systems. Abstract approved: _____________________________________________________________________ Adam J.R. Kent Semi-volatile trace metals like Li, Cu, Mo, Sn, In, and Pb have the potential to track mobility of a volatile phase in volcanic systems. In this dissertation four studies are presented that either directly investigate or are motivated by observations of trace metal behavior in volcanic systems. A common tool for trace element determination in solid materials is laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Although this technique has the potential to measure concentrations of many elements to << 1 ppm, it also has the potential to fractionate elements of different volatility resulting in increased analytical uncertainty. Potential sources of fractionation in two different laser ablation systems are characterized, including a previously unrecognized source of fractionation related to differential carrier gas flow at the site of ablation. Glass and melt inclusions from the 1959 eruption of Kilauea Iki record little evidence for volatile behavior of metals, but do record variations related to mixing of distinct batches of magma. Variations in concentrations of metals like Cu, Zn, and Mo can be explained with olivine fractionation. Only Sn variations appear to be compatible with volatile mobility. Lithophile element variations in both glass and melt inclusions require that the Kilauea Iki magma was a mixture of melts generated from different mantle sources by variable degrees of melting. Amphibole phenocrysts from Mt. Pinatubo, Mt. Hood, Mt. St. Helens, and Shiveluch Volcano record a variety of trace element signatures related to the sources and fractionation processes acting in each of these systems. Variations in Li and Cu in amphiboles are decoupled from any other trace element but positively correlate with each other. Their behavior appears to be consistent with mobility in volatile-rich fluids followed by rapid equilibration with amphibole phenocrysts. New 40Ar-39Ar incremental heating age determinations and whole rock major and trace element analyses from the Curaçao Lava Formation and the Dumisseau Formation have provided a revision of the timing and geochemical character of the Caribbean Large Igneous Province. These data provide evidence for almost 30 million years of volcanic history beginning around 94-60 Ma with mantle plume-like geochemical character. To reconcile the duration of volcanism and the observed geochemical signature with models of mantle plume impingement, a new model for development of the Caribbean Large Igneous Province is proposed that calls on nearby subduction zones to induce asthenospheric flow in the mantle that allows for continuous tapping of plume-influenced mantle for a 30 million year period. ©Copyright by Matthew W. Loewen December 16, 2013 All Rights Reserved Volatile Mobility of Trace Metals in Volcanic Systems by Matthew W. Loewen A DISSERTATION submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented December 16, 2013 Commencement June 2014 Doctor of Philosophy dissertation of Matthew W. Loewen presented on December 16, 2013. APPROVED: Major Professor, representing Geology Dean of the College of Earth, Ocean, and Atmospheric Sciences Dean of the Graduate School I understand that my dissertation will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my dissertation to any reader upon request. Matthew W. Loewen, Author ACKNOWLEDGEMENTS A small acknowledgements section at the beginning of this dissertation cannot properly thank or even recognize all of the many people who made completing this work possible and more importantly enjoyable. In each chapter separate acknowledgement sections address important logistical support, funding, and reviews that went into each chapter. Here I want to recognize people who were most important to my completion of this overall degree. First I want to note my appreciation for Adam Kent, my advisor, and the members of my thesis committee: Bob Duncan, John Dilles, Frank Tepley, and Anthony Koppers as well as late substitutes for my defense Anita Grunder and Dave Graham who stepped in after a beautiful December snowstorm cancelled my original defense date and required me to reschedule for a time when Bob and John could not attend. I could not ask for a better advisor than Adam. He trusted me with the freedom to work out my own problems and work on my own schedule, but also readily answered questions and gave exceptional guidance on how to write. The data we collected often was unexpected and quite frankly disappointing, but he kept me positive and helped to point out the value of whatever results we found. All of my committee members have provided support beyond their required rolls. Bob has acted more like a co-advisor, especially with the Caribbean project, and made huge contributions to publishing that chapter before my defense. I have only been able to apply a fraction of John’s wealth of knowledge to the discussion of metal behavior in volcanic systems, and all of his suggestions including those not included here will help improve the eventual publications of those projects. In addition, I am grateful to have had the opportunity to learn from him by working as his teaching assistant in Mineralogy and taking several of his courses. Frank was always a friendly face with his office down the hall from mine. I probably dropped in on him and asked him for as much advise as I asked Adam for. Most importantly, he was always willing to help and take the time to listen. Anthony played the role of a GCR, but actually taught me how to prepare samples for Ar-Ar dating and gave me my first examination on the literature of the Caribbean LIP during his isotope geochemistry class. ACKNOWLEDGEMENTS (Continued) Beyond my committee, I want to acknowledge the entire VIPER community of fellow students and faculty. While working at OSU, I had the fortune to work with a group of genuinely good people who made work fun. The students who were here when I arrived established a culture of friendliness and excitement. I especially want to acknowledge the conversation and friendships with Alison Koleszar, Mark Ford, Allison Weinsteiger, Morgan Salisbury, BJ Walker, and Erin Lieuallen. My cohort of incoming VIPERs in 2008-09, Ashley Bromley, Amy Lange, and Fede Cernuschi, still blow me away with their intelligence, but they are also the best people I could ever hope to work with and are among my best friends. Ashley especially has become a lifelong friend in all adventures geologic and union. New students have come (and gone) since I got here and I don’t know half of them as well as I’d like, but I want to point out some who have been especially helpful as sounding boards and friends including Dale Burns, Jason Kaiser, Stephanie Grocke, Kyle Krawl, Richard Bradshaw, Luc Farmer, Christine Chan, Daniel Eungard, Andrew Burleigh, Casey Tierney, Darrick Boschmann. The good nature of most people who have chosen to join the VIPER group at OSU is this research programs’ strongest asset. Outside of the VIPER group, I have been lucky to be involved in the Coalition of Graduate Employees (CGE 6069). This is the best organization I have ever been a part of and have been proud to be a member and volunteer. The people I have met in this organization are some of the most generous people I know and have made meaningful improvements in both Oregon State University and the university/research communities around the country. I think the best work I’ve done while working on a PhD are not in this dissertation but with this organization. I hope as long as CGE represents graduate employees at OSU people do not hesitate to join this great union and continue to volunteer to make it better. ACKNOWLEDGEMENTS (Continued) Before coming to OSU many important people inspired me to not only study first in the sciences but then geology. Dr. Kaser was an especially inspiration high school physics/astronomy teacher. My undergraduate advisor, Jeff Tepper, is a geologic role model and taught me my core skills in this wonderful subject. Two of my closest friends as an undergraduate, Eric and Marissa, helped drive my passion and excitement in all things scientific and academic. My immediate and extended family has been a big part of my life and gave me the encouragement and support to get through all my schooling. I have ben fortunate to have them close the last few years even if school has kept me too busy to see everyone as much as I would like. I want to especially note my Dad from whom I inherited a love for debate, thinking, and standing up for what is right, and my Mom who taught me to love the mountains and the world around me. Studying geology for almost 10 years now started with exploring the spectacular volcanoes of the central Cascades in Oregon. My most important acknowledgement is reserved for my best friend and wife, Caitlin. When I started at OSU she lived in McMinnville and then Portland. Without the fun of visiting her almost every weekend my first two years in grad school I would have burned out and never continued past a masters degree. After marrying me and living with me she has been my most important companion sharing my excitement and comforting my dismay through all of my experiences the last few years. My best memories in graduate school have been adventures with her and those experiences are what fueled my ability to work hard on my degree.